1. Field of the Invention
The present invention relates to a particle analyzer and a particle analyzing method. In particular, it relates to a particle analyzer for preparing two-dimensional frequency distribution maps (scattergrams) by using characteristic parameters of particles and classifying the particles indicated on the distribution maps to determine the kind and the number of the particles.
2. Description of Related Art
In the field of the particle analyzer of this kind, conventionally known is a particle analyzer which presets a plurality of regions on a two-dimensional frequency distribution map and calculates degrees of attribution of particles indicated on the distribution map with respect to the preset regions to classify the particles based on the calculated attribution degrees (see Japanese Unexamined Patent Publication No. Hei 6 (1994)-3252, for example). Moreover, known is a method for classifying and counting leukocytes in which the leukocytes are classified into five groups by using two kinds of reagents (see U.S. Pat. No. 5,677,183, for example).
However, if the conventional particle analyzer is used to analyze blood cells contained in blood, particle clusters which will appear on the two-dimensional frequency distribution map may be shifted when characteristic parameters used for preparing the distribution map are varied depending on some factors, e.g., the kind and amount of a reagent for diluting the blood to be analyzed, contamination of a detector for detecting electric or optical data from the blood cells, or variation in amplification degree of an electric circuit for converting the detected data into an electric signal to obtain the characteristic parameters. Therefore, accurate classification cannot be carried out and false analysis results may be obtained.